Extraction kinetics of rare earth elements with sec-octylphenoxy acetic acid

The kinetics of RE (La, Gd, Er, Yb and Y) extraction with sec-octylphenoxy acetic acid was investigated using a constant interfacial area cell with laminar flow at 303 K. The natures of the extracted complexes have some effect on the extraction rate which is controlled by the reaction rate of M(III) and extractant molecules at two-phase interface for Er(III), Yb(III) and Y(III), by a mixed chemical reaction-diffusion for Gd(III) and a diffusion for La( III). The extractant molecules tend to adsorb at the interface. So an interfacial extraction reaction model was derived.

Influence of cation concentration on 7,7,8,8-tetracyanoquinodimethane in polyelectrolyte by using in-situ microscopic Fourier transform infrared spectroelectrochemistry

The ion pair between the dianion of 7,7,8, 8-tetracyanoquinodimethane(TCNQ) and Li+ were investigated by in - situ microscopic Fourier transform infrared( FTIR) spectroelectrochemical technique. The effect of ion pair increases with increasing the concentration of cation. We observed a new band at 2130 cm(-1).

聚电解质中阳离子浓度对7,7,8,8-四氰基苯醌二甲烷现场显微红外光谱的影响

用现场显微红外光谱电化学技术研究了聚电解质中TCNQ在电化学还原过程中二价阴离子与Li~+离子之间形成的离子对.离子对效应随阳离子浓度增加而增大.观察到一个文献中未曾报道的谱带位于2130cm~(-1)附近.

LB膜模板诱导晶体取向生长

LB膜作为模板可诱导晶体取向成核和外延生长，生成的晶体材料具有独特的微观结构和优异的物理化学性能。这种方法对于生物矿化现象的研究以及新颖材料合成策略的设计等方面具有重要的启示意义。本文从LB膜诱导晶体取向生长的机理及利用等方面综述了该领域研究的最新进展。

Ring-opening polymerization of epsilon-caprolactone by lanthanocene catalysis

Ring-opening polymerization of epsilon-caprolactone (CL) catalyzed by lanthanocenes, O(C2H4C5H3CH3)(2)YCl (Cat-YCl) and Me2Si[(CH3)(3)SiC5R3](2)NdCl (Cat-NdCl) has been carried out for the first time. It has been found that both yttrocene and neodymocene are very efficient to catalyze the polymerization of CL, giving high molecular weight poly(epsilon-caprolactone) (PCL). The effects of [cat]/[epsilon-CL] molar ratio, polymerization temperature and time, as well as solvents were investigated and polymerization temperature is found to be the most important factor affecting the polymerization. The bulk polymerization gives higher molecular weight PCL and higher conversion than that in solution polymerization. NaBPh4 was found to promote the polymerization of epsilon-caprolactone, and thus to increase both the polymerization conversion and MW of poly(epsilon-caprolactone).

Macrocyclic oligomeric arylene ether ketones: Synthesis and polymerization

Some novel macrocylic(arylene ether ketone)oligomers were synthesized in high yields by a nucleophilic aromatic substitution reaction of 4,4'-dinitrobenzophenone with bisphenols in the presence of anhydrous potassium carbonate under pseudo-high-dilution conditions. Detailed structural characterization of these oligomers by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS), H-1 NMR and FT-IR confirmed their cyclic nature and the compositions of the oligomeric mixtures was indicated by GPC analysis. Ring-opening polymerization of cyclic oligomers 3a to a high molecular weight polymer with M-w of 52.3 and M-n of 17.2 k was achieved by heating at 280 degrees C for 40 min in the presence of a nucleophilic initiator.

Red color filter in an organo-soluble polyamide matrix for liquid crystal displays

A red color filter was laminated from a solution of red color pigment and an organo-soluble polyamide, based on 1,4-bis(3,4-dicarboxyphenoxy) benzene dianhydride (HQDPA) and 2,2'-dimethyl-4,4'-methylene dianiline (DMMDA). The red color filter in a polyamide matrix with negative birefringence plays an important role in twisted nematic liquid crystal displays (TN-LCDs). The red color filter, and also compensation films, extend the viewing angle of LCDs. (C) 1997 Elsevier Science S.A.

Direct deposition and characterization of Langmuir-Blodgett monolayers of soluble polyimides

Langmuir-Blodgett (LB) monolayers of three kinds of soluble polyimides were prepared with the direct deposition method, The monolayer structures were characterized with W-vis absorption spectroscopy, the wide angle X-ray scattering method and electrochemical techniques. The polyimide molecules in the LB monolayers lie orderly on the substrate surfaces with the orientation in which the dianhydride group is normal to the substrate surface and two carbonyl oxygen groups close to the surface. Therefore, the thickness of the three kinds of polyimide LB monolayers are the same because it depends on the distance between the two carbonyl oxygen groups in the same ring. The area of monomeric units are dependent on the length of the diamine group. The model of the molecular packing proposed from the quantomechanical calculation is in good agreement with the experimental results. (C) 1997 Elsevier Science S.A.

A study of the radical reaction of C-60 with n-Bu(3)SnH

The reaction of buckministerfullerene (C-60) with tri-n-blltyltin hydride(n-Bu(3)SnH) in toluene solution has been investigated. According to mass spectrometry analysis, the products of above reaction are C-60(BuH)(n)(n = 1 similar to 3) and Bu(x)Sn(y)H(x) (x = 3 similar to 8, y = 1 similar to 4,approximate to = 0 similar to 3). The reaction maybe provide a new method for the synthesis of alkylated fullerene derivatives. Where C-60 also takes a role of a catalysis of organtic-tin polymerization. The radical reaction mechanism has been discussed.

C_（60）与n－Bu_3SnH的自由基反应研究

Ｃ_（６０）与ｎ－Ｂｕ_３ＳｎＨ的自由基反应研究余益民，郭兴华，刘子阳，刘淑莹，傅芳信，钱明星（中国科学院长春应用化学研究所，长春，１３００２２）（东北师范大学化学系）关键词自由基反应，富勒烯，三丁基锡氢化物，自由基海绵自Ｋｒａｔｓｃｈｍｅｒ等［１］实...

EFFECTS OF STRUCTURE MULTIPLICITY ON MECHANISM OF RADIATION CROSS-LINKING OF POLYMERS

In an attempt to explore the effects of structural multiplicity of polymers on the mechanism of radiation crosslinking, the adaptability of the Charlesby-Pinner's equation and its various modified versions are examined. It is recognized that both chemical

A Study of the Heterogenization of Heteropoly Acid (II)

The surface chemical species of surface-modified activated carbons and adsorption of 12-silicotungstic acid (SiW12) on them were studied It was found that these carbons have different adsorption isotherms and adsorptive force. The carbonyl groups on the s

杂多酸的固载化研究(Ⅱ)

研究了以多种方法化学改性的不同活性炭表面化学特性及十二硅钨酸（SiW12）在相应表面的吸附.首次提出，不同原料来源和改性的活性炭对SiW12的吸附有不同的等温线形式和吸附力.活性炭表面的羰基有利于SiW12的吸附，而表面的羧基则是不利的.

HOST-GUEST INTERACTIONS OF THIAMINE WITH ANIONS - CRYSTAL-STRUCTURE OF THIAMINE IODIDE SESQUIHYDRATE

The crystal structure of thiamine iodide sesquihydrate has been determined by X-ray diffraction methods as a host-guest model for coenzyme-substrate interactions. The asymmetric unit contains two chemical units. Both the thiamine molecules A and B, which are crystallographically independent, assume the usual F conformation and have a disordered hydroxyethyl side chain. An iodide anion (or a water molecule) bridges the pyrimidine and thiazolium rings of molecule A (or B) by forming a hydrogen bond with the amino group and an electrostatic contact with the thiazolium ring to stabilize the molecular conformation. In the crystal the thiamine molecules self-associate to form a pipe-like polymeric structure, in which four thiamine hosts surround an iodide guest and hold it through C(2)-H...I hydrogen bonds and thiazolium...I electrostatic interactions. Crystal data: C12H17N4OS+.I- . 1.5 H2O, monoclinic, P2(1)/c, a = 12.585(2), b = 25.303(5), c = 12.030(2) angstrom, beta = 115.15(1)degrees, V = 3468(1) angtrom3, Z = 8, D(c) = 1.606 g cm-3, R = 0.045 for 3328 observed reflections.